This invention relates to a novel dental temporary filling material/cement comprising an inert viscous hydrophobic matrix in which fine solid particles are dispersed such that, upon reaction with water and/or certain organic polyacids, the physical form of such blend is transformed from that of a moldable paste to a solid. The high concentration of hydrophilic solid particles ensures water conductivity through the mass of the material. Such moisture penetration is critical to achieve a satisfactory depth of cure, as measured as a distance from the saliva/restoration borders.
In this invention, the role of the dispersed solid particles is, therefore, of dual nature:
As components responsible for the cure of the cement and its final mechanical properties, and PA1 As moisture conductors through the mass of the restoration. PA1 Reaction of salts and/or oxides with water or formation, of adducts of salts and waters, and PA1 Reaction of alkaline glass sites with polyacids, or the reaction of such polyacids with metal oxides, hydroxides, or salts of such materials, with weak organic acids. PA1 Self cured materials, usually representing a two part system in which the curing process is initiated by mixing the two components; PA1 Light cured materials, usually a one part system in which the curing process is initiated by irradiation with high intensity light; and PA1 Saliva cured materials, in which curing occurs as a result of hydration of inorganic components of the formulations.
The curing of the materials of this invention occurs as a result of two types of chemical processes occurring simultaneously:
The chemical composition of the formulations of this invention resulted in cements featuring highly desirable characteristics. These materials were found particularly suitable for use as temporary restoratives and cements where the ease and speed of application, fast cure, resistance to the oral environment, biological mildness, and ease of removal are of primary concern. Astonishingly, it was further realized that the formulations of this invention, contrary to those of the prior art, show no or minimal volumetric expansion during cure--a feature of critical importance for dental restoratives and cements. An additional advantage is that sustained fluoride release can easily be implemented without negatively affecting the characteristics or the integrity of the restorative.